News / Science & Technology

Research Suggests Prehistoric Man First Influenced Climate Change

Early farmers' use of controlled forest burns, like this one in current-day Uganda, could have begun releasing climate changing gases into the atmosphere 8,000 years ago.
Early farmers' use of controlled forest burns, like this one in current-day Uganda, could have begun releasing climate changing gases into the atmosphere 8,000 years ago.

There is new evidence supporting a controversial theory that humans began changing the earth's climate with the development of agriculture some 8,000 years ago.

In an article published in the journal Nature, researchers studying the theory say new data indicate that enormous amounts of earth-warming greenhouse gases released into the atmosphere by early farming activities helped ward off an impending ice age, and fostered the planet’s current relatively warm, stable climate.  

A more commonly accepted theory suggests that man’s first major influence on the earth’s climate began in the 18th century, at the dawn of the industrial age.   

Scientists say the new findings indicate that the earth was spared from another long deep freeze after the last Ice Age ended 11,000 years ago because of an unusual rise in atmospheric carbon dioxide and methane gas levels starting about 3,000 years later.  

The increase coincided with the advent of farming practices - including the clearing and burning of forests, and maintaining large herds of livestock - that released more of those heat-trapping gases into the atmosphere.

Prehistoric climate expert William Ruddiman of the University of Virginia first proposed the theory in 2003. He said the new findings supporting his hypothesis will be published in a series of papers later this year in a special issue of the journal The Holocene.

Critics of the theory say human populations 8,000 years ago were too small to produce enough greenhouse gases to influence global climate change. And they suggest that other causes, including changes in the earth's orbit and a variety of natural events, could explain the unusual rise in greenhouse gases.

Greenhouse gases are man-made and naturally-occurring gases that trap solar heat in the earth’s atmosphere.

Most scientists now believe that modern man’s burning of fossil fuels and the clearing of forests over the past two centuries have intensified the so-called "Greenhouse Effect" and have caused a gradual warming of the earth's climate.

You May Like

Photogallery Americans Celebrate Thanksgiving With Feasts, Festivities

Holiday traditions include turkey dinners, 'turkey trots,' American-style football and New York parade with giant balloons More

Video For Obama, Ferguson Violence is a Personal Issue

With two years left in term, analysts say, president has less to lose by taking conversation on race further More

Video Italian Espresso Expands Into Space

When Italian astronaut Samantha Cristoforetti headed for the ISS, her countrymen worried how she would survive six months drinking only instant coffee More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
South Africa Sees Male Circumcision as Way to Reduce HIV Infectionsi
X
November 28, 2014 3:31 PM
South Africa remains plagued by AIDS despite massive government and NGO efforts on prevention and life-sustaining Anti-Retro-Viral programs. But the country has opened up another front to reduce new HIV infections: promoting circumcision. Emilie Iob reports for VOA News from a pioneering circumcision center in Orange Farm, Johannesburg.
Video

Video South Africa Sees Male Circumcision as Way to Reduce HIV Infections

South Africa remains plagued by AIDS despite massive government and NGO efforts on prevention and life-sustaining Anti-Retro-Viral programs. But the country has opened up another front to reduce new HIV infections: promoting circumcision. Emilie Iob reports for VOA News from a pioneering circumcision center in Orange Farm, Johannesburg.
Video

Video To Make A Living, Nairobi Street Vendors Face Legal Hurdles, Physical Violence

The Nairobi City Council has been accused of brutality in dealing with hawkers in the Central Business District - in order to stop them from illegally selling their wares on the streets. Lenny Ruvaga has more for VOA News from the Kenyan capital.
Video

Video For Obama, Ferguson Violence is a Personal Issue

Throughout the crisis in Ferguson, Missouri, President Barack Obama has urged calm, restraint and respect for the rule of law. But the events in Ferguson have prompted him to call — more openly than he has before — for profound changes to end the racism and distrust that he believes still exists between whites and blacks in the United States. VOA White House correspondent Luis Ramirez reports.
Video

Video Online Magazine Gets Kids Discussing Big Questions

Teen culture in America is often criticized for being superficial. But an online magazine has been encouraging some teenagers to explore deeper issues, and rewarding their efforts. VOA religion reporter Jerome Socolovsky went to this year’s Kidspirit awards ceremony in New York.
Video

Video US Community Kicks Off Thanksgiving With Parade

Thursday is Thanksgiving in the United States, a holiday whose roots go back to the country's earliest days as a British colony. One way Americans celebrate the occasion is with parades. Anush Avetisyan takes us to one such event on the day before Thanksgiving near Washington, where a community's diversity is on display. Joy Wagner narrates
Video

Video Aung San Suu Kyi: Myanmar Opposition to Keep Pushing for Constitutional Change

Myanmar opposition leader Aung San Suu Kyi says she and her supporters will continue pushing to amend a constitutional clause that bars her from running for president next year. VOA's Than Lwin Htun reports from the capital Naypyitaw in this report narrated by Colin Lovett.
Video

Video Mali Attempts to Shut Down Ebola Transmission Chain

Senegal and Nigeria were able to stop small Ebola outbreaks by closely monitoring those who had contact with the sick person and quickly isolating anyone with symptoms. Mali is now scrambling to do the same. VOA’s Anne Look reports from Mali on what the country is doing to shut down the chain of transmission.
Video

Video Ukraine Marks Anniversary of Deadly 1930s Famine

During a commemoration for millions who died of starvation in Ukraine in the early 1930s, President Petro Poroshenko lashed out at Soviet-era totalitarianism for causing the deaths and accused today’s Russian-backed rebels in the east of using similar tactics. VOA’s Daniel Shearf reports from Kyiv.
Video

Video Hong Kong Protests at a Crossroads

New public opinion polls in Hong Kong indicate declining support for pro-democracy demonstrations after weeks of street protests. VOA’s Bill Ide in Guangzhou and Pros Laput in Hong Kong spoke with protesters and observers about whether demonstrators have been too aggressive in pushing for change.
Video

Video US Immigration Relief Imminent for Mixed-Status Families

Tens of thousands of undocumented immigrants in the Washington, D.C., area may benefit from a controversial presidential order announced this week. It's not a path to citizenship, as some activists hoped. But it will allow more immigrants who arrived as children or who have citizen children, to avoid deportation and work legally. VOA's Victoria Macchi talks with one young man who benefited from an earlier presidential order, and whose parents may now benefit after years of living in fear.
Video

Video New Skateboard Defies Gravity

A futuristic dream only a couple of decades ago, the hoverboard – a skateboard that floats above the ground - has finally been made possible. While still not ready for mass production, it promises to become a cool mode of transport... at least over some surfaces. VOA’s George Putic reports.
Video

Video Falling Gas Prices Impact US Oil Extraction

With the price of oil now less than $80 a barrel, motorists throughout the United States are benefiting from gas prices below $3 a gallon. But as VOA’s Kane Farabaugh reports, the decreasing price of petroleum has a downside for the hydraulic fracturing industry in the United States.

All About America

AppleAndroid